What medium to use?, Soda, Sand, Walnut, Plastic, etc. Options

[Poor-sche Lover]

I have recently gained access to a high quality sandblaster, but I really don't know much about the process. I have a few questions.

1) Do I have to use sand for the blaster, or can I use something else in it? I've heard that you can't use soda because of the way it feeds into the system?

2) I want to use soda because it's less abrasive, but I read that soda will not remove the rust. I definitely need to remove the rust. Which type of medium is best for this?

3) Can you give me any general advantages/disadvantages of soda, sand, walnut, or plastic? Any others that I don't know about?

Any advice/suggestions/info you could provide would be helpful. Nobody around really does this, so farming it out isn't a viable option. It's either this or the long way, and I'd really like to blast if I can. Thanks for your help, guys.

[Pistachio]

QUOTE (Korijo @ Mar 18 2006, 07:59 PM)

QUOTE Will the medium grit walnut shell do anything to potential rust? it'll blast it away..

Now that's interesting - It was my understanding that the advantages of the "soft" abrasives (wal shells, poly, etc) was that they clean without etching the metal. Hence they're the snitz for cleaning things like delicate trim, machined surfaces, or soft metal parts & for paint removal on large body panels. Because of the media's soft nature, they work without the heat buildup that'll warp body panels ala sand with an inexperianced operator. However, the trade for their nice non-etching nature, is that they absolutely suck at rust removal. (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

The guy I know that does poly-stripping for the street rodders & restorers in N. NV, strips the paint off the car using the poly media and then goes back & spot blasts any "rusty" areas with aluminum oxide. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)


Yeah walnut shells will work in "any" blaster. The price depends alot on your supplier/whether or not they sell it all the time or are special ordering it for you & where you are. From my experiance anything in the $0.72-76/lb range is about right. I have no idea how much it would take to blast an entire car, but I wouldn't plan on re-using it much. Which is one advantage poly has over shells if you're blasting in an enclosed space - you can sweep it up, screen it & reuse it. Which justifies it's "twice the price" nature to buy in. On the other hand, walnut shells are bio-degradeable & will disappear into your lawn/yard- the paint won't, but the shells will.

IMO one of the biggest things people underestimate with blasting (in a cabinet or otherwise) is the importance of an absolutely dry air source and the volume of air they're going to need to make themselves happy (& yeah, the media needs to be "dry" too). Dry air is a must to prevent clogging issues & it takes a fair infrastucture to get it that way - one of those little "air dryer" filters that Sears sells hung off your air compressor ain't going to do it! Ya gotta cool it to dry it. And again, JMO, you're going to get bored & disgusted before you get a single fender done if you're going to try and use a little 50CFM single stage 5HP compressor. You need volume to blast effiecantly - CFM not PSI.

Yeah ok, somepeople have more time than money, but I think if I were going to try and blast an entire car - I'd go rent a huge 2000CFM, industrail compressor for the weekend and be done with the car, than spend six weeks trying to do it with my 7hp two-stage.

That's all JMO of course.